title: Transfusion of 1 and 2 units of red blood cells is associated with increased morbidity and mortality.
abstract: BACKGROUND
  This study examined the relationship between transfusion of 1 or 2 units of red blood cells (RBCs) and the risk of morbidity and mortality after isolated on-pump coronary artery bypass grafting (CABG).
  
  
  METHODS
  A total of 22,785 consecutive patients underwent isolated on-pump CABG between January 1, 2008, and December 31, 2011 in Michigan. We excluded 5,950 patients who received three or more RBC units. Twenty-one preoperative variables significantly associated with transfusion by univariate analysis were included in a logistic regression model predicting transfusion, and propensity scores were calculated. Transfusion and the propensity score covariate were included in additional logistic regression models predicting mortality and each of 11 postoperative outcomes.
  
  
  RESULTS
  Operative mortality for the study cohort of 16,835 patients was 0.8% overall, 0.5% for the 10,884 patients with no transfusion, and 1.3% for the 5,951 patients who received transfusion of 1 or 2 units (odds ratio 2.44; confidence interval 1.74 to 3.42; p < 0.0001). The association between transfusion and mortality lessened after propensity adjustment but remained highly significant (odds ratio 1.86; confidence interval 1.21 to 2.87; p = 0.005). Of the 11 postoperative outcomes studied, all but sternal wound infection and need for dialysis were also significantly associated with transfusion.
  
  
  CONCLUSIONS
  Transfusion of as little as 1 or 2 units of RBCs is common and is significantly associated with increased morbidity and mortality after on-pump CABG. The relationship persists after adjustment for preoperative risk factors. These results suggest that aggressive attempts at blood conservation and avoidance of even small amounts of RBC transfusion may improve outcomes after CABG.
authors.affiliation: Division of Cardiac Surgery, Henry Ford Hospital, University of Michigan, Detroit, Michigan. Electronic address: gpaone1@hfhs.org.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Paone
authors.affiliation: Section of Health Services Research and Quality, Department of Cardiac Surgery, University of Michigan, Detroit, Michigan.
authors.forename: Donald S
authors.initials: DS
authors.lastname: Likosky
authors.affiliation: Division of Cardiac Surgery, Henry Ford Hospital, University of Michigan, Detroit, Michigan.
authors.forename: Robert
authors.initials: R
authors.lastname: Brewer
authors.affiliation: Michigan Society of Thoracic and Cardiovascular Surgeons Quality Collaborative, University of Michigan, Detroit, Michigan.
authors.forename: Patricia F
authors.initials: PF
authors.lastname: Theurer
authors.affiliation: Michigan Society of Thoracic and Cardiovascular Surgeons Quality Collaborative, University of Michigan, Detroit, Michigan.
authors.forename: Gail F
authors.initials: GF
authors.lastname: Bell
authors.affiliation: Department of Public Health Services, Henry Ford Hospital, University of Michigan, Detroit, Michigan.
authors.forename: Chad M
authors.initials: CM
authors.lastname: Cogan
authors.affiliation: Section of Adult Cardiac Surgery, Department of Cardiac Surgery, University of Michigan, Detroit, Michigan.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Prager
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D002315:Cardiopulmonary Bypass / Q000379:methods; D016022:Case-Control Studies; D002423:Cause of Death; D016001:Confidence Intervals; D001026:Coronary Artery Bypass / Q000009:adverse effects / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000601:surgery*; D017707:Erythrocyte Transfusion / Q000009:adverse effects* / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D017052:Hospital Mortality / Q000639:trends*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011183:Postoperative Complications / Q000401:mortality / Q000503:physiopathology; D011237:Predictive Value of Tests; D011859:Radiography; D012016:Reference Values; D012189:Retrospective Studies; D018570:Risk Assessment; D016019:Survival Analysis
keywords: 18